1. Field of the Invention
The present invention relates to a structure of a semiconductor device having high packaging density. In particular, the present invention relates to a semiconductor device structure that can facilitate heat dissipation (heat release to the outside).
2. Description of the Related Art
One proposal for facilitating heat dissipation (heat radiation, heat release) from a single device in the field of semiconductor technology is disclosed in Japanese Patent Application Kokai (Publication) No 2006-032453. A Peltier element is incorporated in the device to cool the device (and release heat) from the device. With the downsizing and increasing functionality of equipment, on the other hand, various types of assembly are adopted. One example is a multi-chip package or MCP. One structure used for heat dissipation from the MCP is disclosed in Japanese Patent Application Kokai No. 2004-228485. A cooler chip including a Peltier element is disposed below a plurality of stacked integrated circuit (IC) chips.
A cooling principle (Peltier effect) using a Peltier element will be described in brief. Two different kinds of metals or semiconductors are electrically connected to each other in series. When electric current flows in the metals (or the semiconductors), endothermic and exothermic actions excluding Joule's heat occur at the connection between the metals (or the semiconductors). This phenomenon is called a Peltier effect. The Peltier element is a module using such a Peltier effect. An N type semiconductor and a P type semiconductor are connected in series to each other via a conductor, such as a metal. When predetermined electric current flows in the series-connected structure, endothermic and exothermic actions occur depending upon the flowing direction of the electric current. Thus, the Peltier element is a thermoelectric conversion element. For example, when electric current flows in a direction of a conductor A→an N type semiconductor→a conductor B→a P type semiconductor→a conductor C, then an endothermic phenomenon occurs in the conductor B, and an exothermic phenomenon occurs in the conductor A and the conductor C.
A silicon interposer (Si-IP) is used if a plurality of IC chips are mounted on a surface of a module (if a package does not include stacked IC chips). When the silicon interposer is used, it is possible to provide micro wiring. Accordingly, a module can have higher functionality and higher density. If the module has the silicon interposer, on the other hand, it is necessary to increase heat dissipation.